A pleated screen is an apparatus where a screen configured to be foldable in a zigzag manner in the vertical direction is suspended from a head box, and the screen is raised and lowered by an operation apparatus so as to adjust an amount of lighting arbitrarily.
As a kind of such a pleated screen, one is known which is provided with a bottom rail and a middle rail, and configured such that the middle rail is attached to an bottom end of an upper screen which is suspended from a head box, and the bottom rail is attached to an bottom end of a lower screen which is suspended from the middle rail. The upper screen is made, for example, of a semipermeable texture, such as lace fabric, which allows part of light to permeate, and the lower screen is made of a texture having a light-blocking property.
Further, operation apparatuses are provided for raising and lowering the middle rail and the bottom rail, respectively, so that the middle rail and the bottom rail can be raised and lowered independently from each other by each of the operation apparatuses. With this configuration, when the bottom rail and the middle rail are lowered to their lower limits, a window area can be covered with the semipermeable upper screen, and when the bottom rail is lowered to its lower limit and the middle rail is raised to its upper limit, the window area can be covered with the lower screen having the light-blocking property.
When the bottom rail is lowered to its lower limit and the middle rail is lowered to an intermediary position, it is also possible to cover the top half of the window area with the semipermeable screen and the bottom half of the window area with the light-blocking screen.